[Python / PeriodicCubicalComplex and CubicalComplex] cofaces_of_persistence_pairs requires compute_persistence

[VincentRouvreau]

PeriodicCubicalComplex.cofaces_of_persistence_pairs and CubicalComplex.cofaces_of_persistence_pairs require a note to explain that cofaces_of_persistence_pairs requires compute_persistence() function to be launched first. (cf. betti numbers method)

[mglisse]

Maybe at the same time, some methods still say they require persistence() when they should say compute_persistence(), probably they were in a branch when the others were changed.